Nathan Weizenbaum's Lisp scanner

nathany · nathany · commit 3f69ed0e2454 · 2012-10-27T13:46:49.000-06:00
diff --git a/lib/coderay/scanners/lisp.rb b/lib/coderay/scanners/lisp.rb
@@ -0,0 +1,102 @@
+# By Nathan Weizenbaum (http://nex3.leeweiz.net)
+# MIT License (http://www.opensource.org/licenses/mit-license.php)
+#
+# CodeRay scanner for Lisp.
+# The keywords are mostly geared towards Emacs Lisp,
+# but it should work fine for Common Lisp
+# and reasonably well for Scheme.
+
+require 'rubygems'
+require 'coderay'
+
+module CodeRay::Scanners
+  class Lisp < Scanner
+    register_for :lisp
+
+    NON_SYMBOL_CHARS = '();\s\[\]'
+    SYMBOL_RE = /[^#{NON_SYMBOL_CHARS}]+/
+    EXPONENT_RE = /(e[\-+]?[0-9]+)?/
+
+    GEN_DEFINES = %w{
+      defun defun* defsubst defmacro defadvice define-skeleton define-minor-mode
+      define-global-minor-mode define-globalized-minor-mode define-derived-mode
+      define-generic-mode define-compiler-macro define-modify-macro defsetf
+      define-setf-expander define-method-combination defgeneric defmethod
+    }
+    TYPE_DEFINES = %w{
+      defgroup deftheme deftype defstruct defclass define-condition
+      define-widget defface defpackage
+    }
+    VAR_DEFINES = %w{
+      defvar defconst defconstant defcustom defparameter define-symbol-macro
+    }
+    KEYWORDS = (GEN_DEFINES + TYPE_DEFINES + VAR_DEFINES + %w{
+      lambda autoload progn prog1 prog2 save-excursion save-window-excursion
+      save-selected-window save-restriction save-match-data save-current-buffer
+      with-current-buffer combine-after-change-calls with-output-to-string
+      with-temp-file with-temp-buffer with-temp-message with-syntax-table let
+      let* while if read-if catch condition-case unwind-protect
+      with-output-to-temp-buffer eval-after-load dolist dotimes when unless
+    }).inject({}) { |memo, str| memo[str] = nil; memo }
+
+    DEFINES = WordList.new.
+      add(GEN_DEFINES, :function).
+      add(TYPE_DEFINES, :class).
+      add(VAR_DEFINES, :variable)
+
+    def scan_tokens(tokens, options)
+      defined = false
+      until eos?
+        kind = nil
+        match = nil
+
+        if scan(/\s+/m)
+          kind = :space
+        else
+          if scan(/[\(\)\[\]]/)
+            kind = :delimiter
+          elsif scan(/'+#{SYMBOL_RE}/)
+            kind = :symbol
+          elsif scan(/\&#{SYMBOL_RE}/)
+            kind = :reserved
+          elsif scan(/:#{SYMBOL_RE}/)
+            kind = :constant
+          elsif scan(/\?#{SYMBOL_RE}/)
+            kind = :char
+          elsif match = scan(/"(\\"|[^"])+"/m)
+            tokens << [:open, :string] << ['"', :delimiter] <<
+              [match[1...-1], :content] << ['"', :delimiter] << [:close, :string]
+            next
+          elsif scan(/[\-+]?[0-9]*\.[0-9]+#{EXPONENT_RE}/)
+            kind = :float
+          elsif scan(/[\-+]?[0-9]+#{EXPONENT_RE}/)
+            kind = :integer
+          elsif scan(/;.*$/)
+            kind = :comment
+          elsif scan(SYMBOL_RE)
+            kind = :plain
+
+            if defined
+              kind = defined
+            else
+              sym = matched
+              if KEYWORDS.include? sym
+                kind = :reserved                
+                defined = DEFINES[sym]
+              end
+            end
+          end
+        end
+
+        match ||= matched
+        raise_inspect 'Empty token', tokens unless match
+
+        defined = [:reserved, :comment, :space].include?(kind) && defined
+
+        tokens << [match, kind]
+      end
+
+      tokens
+    end
+  end
+end
